T. Nuns, C. Inguimbert, Jean-Pierre David - ONERA- DPhIEE Displacement Damage Test Guideline Development ESA contract n°4000115513/15/NL/RA/zk T. Nuns, C. Inguimbert, Jean-Pierre David - ONERA- DPhIEE C. Poivey - ESA ESTEC

Context of the study Test standards proposed have existed for some time ESCC25100 for SEE ESCC22900 and MIL-STD-883 G method 1019.9 for TID Goal Support for defining a test plan and conduct irradiations Achieve a harmonization of testing activities Simplification for interpretation, comparison of data Warranty the relevance of the results and hardness assurance for the application But no standard for displacement damages Goal of the study Drafting of an ESCC guideline for displacement damage testing Cover all types of parts sensitive to displacement damage except solar cells Milestones Write a document with recommendations that is submitted to the Component Technology Board (RTB) Radiation Working Group (RWG) for corrections and validation Write a final test guideline Today’s presentation presents some of the ONERA recommendations. They have to be validated by the RWG

References Some existing guidelines Some existing courses "Proton Test Guideline Development – Lessons Learned", S. Buchner, P. Marshall, S. Kniffin and K. LaBel, NASA/Goddard Space Flight Center, 08/22/02. "Spécification générique pour le test d’irradiation des composants optoélectroniques", O. Gilard and G. Quadri, CNES DTC/AQ/EC-2008/06142, 03/13/2008. "CCD Radiation Effects and Test Issues for Satellite Designers", C. J. Marshall and P. W. Marshall, NASA-GSFC Draft 1.0, 10/06/2003. MIL-HDBK-814, Military Handbook, Ionizing dose and neutron hardness assurance guidelines for microcircuits and semiconductor devices, Department of Defense, 02/08/1994. "Guideline for Ground Radiation Testing and Using Optocouplers in the Space Radiation Environment", R. Reed, NASA/Goddard Space Flight Center, 3/28/2002. "Displacement Damage Guideline", M. Robbins, Surrey Satellite Technology LTD, Revision 01.02, 05/16/2014. Some existing courses "Component Characterisation and Testing: Displacement Damage", G. Hopkinson et al., Notes from the RADECS Conference Short Course "Radiation Engineering Methods For Space Applications", Part 4-A, Noordwijk 2003. "Displacement Damage: Analysis and Characterisation of Effects on Devices", G. Hopkinson, Space Radiation Environment and its Effects on Spacecraft Components and Systems (SREC04), part II-03, pp 175–198, Cépaduès Editions, June 2004. (Sre04) "Optoelectronic Devices with Complex Failure Modes", A. Johnston, Notes from the IEEE Nuclear and Space Radiation Effects Conference Short Course, Part 2, Reno NV, 2000. "Radiation Testing and the RHA Process", R. Mangeret, Notes from the RADECS Conference Short Course, Part VI, Oxford, 2013 "Proton Effects and Test Issues for Satellite Designers", P. W. Marshall and C. J. Marshall, Notes from the IEEE Nuclear and Space Radiation Effects Conference Short Course, Norfolk VA, 1999. "Diplacement damage testing", C. Poivey, G. R. Hopkinson, Space Radiation and its Effects on EEE Components, Continuing Education Course, EPFL, Lausanne, Switzerland, 06/09/2009. And publications on the topic…

Outline Context of the study Radiation type and dosimetry Particle type Particle energy Dosimetry Irradiation Level Fluence Flux Irradiation conditions Sample considerations Sample size selection Preparation Measurement conditions Environmental control Possible outline of the guideline

Choice of the particle type Choose mono-energetic particles of the dominant type responsible of the displacement damage at the device level (after the particle transport through the shielding) The relative contribution to non-ionizing energy deposition between protons and electrons depends on the environment and should be evaluated prior choosing the particle type for the ground tests For Earth-orbiting environments, the protons are generally the dominant contribution of the displacement damages In the case of Low Earth Orbit the contribution of electrons is negligible whatever the shielding thickness. But for MEO and GEO orbits that crosses the electrons belts the contribution of electrons is not negligible and can either dominates the degradation for shielding in the range [~10 µm, ~mm]. Notes Electrons deposit a large amount of TID compared to protons It is recommended to separate TID and DD tests Be careful with neutrons. No TID, but: Not dominant particles in space environment Only nuclear type interactions, no coulombic interactions (representativeness issue) NIEL scaling data for other materials than Silicon are still questionable (technical issue) Generally, no mono-energetic neutrons in most facilities (practical issue)

Choice of the particle energy Protons For silicon devices, one energy could be enough NIEL scaling is valid The energy should represent the damage-weighted proton spectrum of the considered mission (most often in the 40 to 60 MeV range for Earth missions) For low shielding application, the most significant contribution comes for low proton energy (typically in the 3-10 MeV range) Walters et al. IEEE Trans. Nucl. Sci., vol. 48, pp. 1773-1777, 2001 For other materials than Si or compound devices (optocouplers) NIEL scaling fails (example GaAs for high proton energies) It is recommended to use 3 or 4 energies representative of the environment at device level Lowest energy range should be sufficient to go through DUT sensitive volume of the DUT and the possible shielding over it (Dewar, lid, window) ⇒ Care should be taken on particle range Electrons > 1MeV to remove uncertainties related to the threshold displacement energy; generally select energies in the 1 to 3 MeV range No data available to determine NIEL scaling of electrons above 5 MeV

Dosimetry considerations Tradeoff between an ideal beam and the practical limits of the standard facilities Energy Energy accuracy Degraders, shielding (window,..) broaden the spectrum of primary beam. It is necessary to evaluate the spectrum that reaches the device (computation, measurements) Energy accuracy +/-5 % ∆E/E < 5% Energy non uniformity: 10% over all irradiated samples Range of particles: energy shall be almost constant: Across the depth of the sensitive volume of tested devices (if known) Across the depth of the die of the tested devices (if the depth of the sensitive volume is unknown) Fluence Fluence accuracy 10% Fluence non uniformity across samples < 10%

Irradiation level and flux 1/2: fluence Fluence and NIEL scaling Use mission equivalent fluence for a given energy instead of displacement damage dose (to avoid using two different NIEL for mission environment definition and test fluence) Test Fluence Related to the Radiation Design Margin (RDM), which is the ratio between the fail equivalent fluence and the mission equivalent fluence The definition of the margins is a project management decision > Mission equivalent Fluence Intermediate fluences are recommended to look at non linear degradation with fluence The bigger the number of steps is, the finer the degradation is known. Suggest at least three intermediate fluence levels When testing at irradiation facility is not possible, use of several sample or masking of device (imagers)

Irradiation level and flux 2/2: flux Flux has little effect, but irradiation time shall be long enough to avoid error on flux measurement and therefore fluence ( > 1 min) High flux causes warming of the device that could induce annealing Flux limits: < 109 protons/cm2/s in the air and < 108 protons/cm2/s in vacuum < 5.109 electrons/cm2/s

Irradiation conditions Air or vacuum? Protons In Air down to 20 MeV Below 30 MeV, distance of Air shall be reduced In vacuum below 20 MeV Electrons In vacuum below 5 MeV In Air above 5 MeV Irradiation temperature Ideally irradiation temperature should be equal to application temperature +/- 10°C Temperature should be maintained up to the last step of irradiation and the post irradiation measurement Bias conditions In general parts shall be unbiased to minimize annealing and TID (all the pins short-circuited and optionally grounded) If operational conditions are known, it is possible to apply these conditions Light Irradiation shall be intentionally performed in the dark Tilt during irradiation Normal irradiation only

Sample considerations Sample size selection The choice of the number of devices that should be selected for the irradiation is managed by two different necessities: The number of fluences and energies to apply if the electro-optical tests cannot be made at the irradiation facility; in this case, one device per fluence and energy is required, The number due to possible part-to-part and batch-to-batch variations Sufficient to cover possible part to part variability Variability should be small of the defects responsible of the electrical degradation are intrinsic or associated to the dopants Variability may be large if the defects are related to impurities Assembly may also be a source of variability (VCSELs, LEDs, optocouplers) Suggested sample numbers 10 samples if the samples are from different batches or are hybrid devices Otherwise, ≥ 4 samples if only one test energy, ≥ 2 samples per energy otherwise Lower sample size for imagers (expensive and possible partial irradiation) An additional control part should be used and tested at each measurement step Sample delidding Generally not necessary with protons >10 MeV (at DUT surface) Recommended for electron irradiations and protons < 10 MeV

Measurement conditions Electrical testing A complete characterization shall be performed before and after irradiation The value of the parameters depend on how the device works in term of biasing conditions, frequency, pattern generator (for imagers), temperature, lighting conditions (for detectors) Measurement conditions shall be adapted to the final application or shall be performed in different representative conditions Time between end of irradiation and measurements Degradation generally maximum just after irradiation Several days are necessary to let the device stabilize Delay between end of irradiation and measurement shall be defined in the test plan and reported One month delay can be a practical reference for comparison between different irradiation even if some measurements are made before Time for stabilization Time for device “cooling” after irradiation and return back to the measurement site (if needed)

Some well known sensitive parameters After C. Poivey (course) and O. Gilard (guideline)

Environmental control Irradiation and measurement temperature Advice to control and report the irradiation temperature Mandatory for low temperature irradiations For room temperature, at least avoid unexpected heating of the samples Advice to control and report the measurement temperature Storage conditions DUT in the dark, pins shorted and at the same temperature as irradiation (±10°C) between irradiation and measurements Annealing No recommendation on annealing in general for low temperature applications, 24 hours at room temperature Other temperatures and duration can be decided at project level and clearly reported Annealing shall be performed after all electro optical measurements after irradiation are completed

Possible outline for the guideline Scope Related documents Terms and definitions Equipment and general procedures Radiation source and dosimetry Radiation Levels Radiation Flux Temperature requirements Electrical measurement systems Test fixture Test setup and requirements Test procedure Test plan Sample selection Radiation exposure and test sequence Electrical measurements Documentation